Bessemer process of making steel



Patented Apr. 16, 1 929.

UNITED STATES PATENT-OFFICE.

FRANK W..DAVIS, or mrnronn, DELAWARE, "assrenon To seminar. a. ALLEN,TRUSTEE.

nnssmm'a rnocnss or MAKING STEEL.

No Drawing.

action of numerous jets of air blown through it, the impurities of theiron, carbon, manganese, silicon and, in the basic process, phosphorusare oxidized, having as a prod not, nearly pure iron. The oxidation ofthe impurities generates the heat necessary for the process. In the acidprocess, silicon 15 contributes largely to the heat generated,

and in the basic process, phosphorus is the big factor. This means thatfor successful operation ofthe Bessemer process, we must use a pig ironhigh in eithersilica or phos- 2o phorus, depending upon whether it isacid or basic. High silicon iron requiring higher fuel consumption inthe blast furnace, demands a correspondingly high price, while highphosphorus iron is not available in the United States in suflicientquantities to make possible a' basic Bessemer industry.

Over fifty percent of the total heat developed by the reactions in theBessemer process is "lost as sensible heat in the waste gases. Anymethod therefor which will make possible. decreasing at will thequantity of this as, (and,.therefore,'the loss of sensible heat Bywaste) will first lower materially the chemibal requirements of theiron, i. e., in the acid process, the silicon, and in the basic, thephosphorus. That is to say, the process may be carried out with what arenow known as non-Bessemer pig. Further, it will relieve the operatorfrom the necessity of 40 mixing various grades of pig iron in order tostart with a more or less definite chemical analysis, as instead ofregulating the amount of heat generated, he will now regulate or securethe temperature of his bath by regulating the amount of heat carriedaway in his gases. My process, therefore, consists in determining thenetblow heat required in any given case and in' so regulatlng thevamount of heat which is wasted as to secure the neces- Application filedJune 2, 1924. Serial No. 717,282.

sary net blow heat. This 'is done through decreasing the amount ofnitrogen in the blast, whereby the waste nitrogen gases will not carryaway more than the allowable proportion of heat, as waste.

It is preferred to obtain the above effects and advantages by regulatingthe oxygen content of the blast. This will be accomplished byenrichingthe air to any percentage oxygen desired, prior to its passagethrough the converter. The oxygen will reduce the proportion of nitrogenin the blast and hence the volume of waste nitrogen gas, the amount ofwhich may be thus controlled.

In addition to the above mentioned features, this process will enablethe operator to finish his metal at a high temperature without danger ofover oxidation. By this practice, he may impartsufficient temperature tothe steel to permit of its being allowed to stand in the ladle aconsiderable time before teeming. Molten steel which is permitted-tostand in this manner will be of a better grade inthat a considerableportion of the included impurities will have the opplertunity to, riseto the surface with the slag There is thus a. time factor not heretoforeavailable, while in addition the metal "is more fluid so that theimpurities in suspension may rise more readily. Hence, 30 the Bessemerprocess is improved.

Further, in the case of the basic process in which phosphorus iseliminated from the bath, the slag so formed will have an appreciableamount of calcium phosphate and may be utilized as a fertilizer.

I claim: 1. The method of carrying out the Bessem r process of makingsteel with noneBesse-' Imer pig which consists in enriching the blastair with oxygen in an amount sufficient to reduce the proportion ofnitrogen in the blast in an amount such that the nitrogen absorbs onlyan allowable proportion of the a heat so' that the net heat of the blowwill satisfy the requirements.

2. The method of making ahigh phosphorus slag which may be used forfertilizer, when using an iron in which the. phosphorus is too low to beclassed as a basic Bessemer 1 amount of oxygen to the amount of inertgases in theblast so as to reduce the heat in the waste to the pointwhich will give them blow heat required.

In testimony whereof, I have hereunto signed my name.

FRANK W. DAVIS.

